Aromatics hydrogenation in the presence of sulfur

ABSTRACT

A process is disclosed for reducing the amount of aromatics contaminants, and any sulfur contaminants present, in a hydrocarbon feedstock boiling in the range 500*-1050*F., comprised predominantly of paraffin hydrocarbons to produce a White Oil containing no more than about 5 ppm sulfur and 8 ppm aromatics. The feedstock, together with hydrogen, is contacted in a reaction zone with a catalyst comprising palladium and mordenite at a temperature in the range 300*-700*F., an LHSV from 0.1 to 20, a pressure from 100 psig to 3000 psig, and a hydrogen supply rate of 500 to 20,000 SCF/barrel of feedstock. The mordenite has been exchanged to an extent of 5-80% of the available ion-exchange sites with a multivalent metal.

United States Patent [1 1 Michlmayr Nov. 4, 1975 [75] Inventor: Manfred Josef Michlmayr, Walnut Creek, Calif.

[73] Assignee: Chevron Research Company, San Francisco, Calif.

[22] Filed: Feb. 3, 1975 [21] Appl. No.: 546,663

Related US. Application Data [63] Continuation-impart of Ser. No. 372,894, June 22,

1973, Pat. No. 3,876,529.

[52] US. Cl. 208/144; 208/217; 260/667; 208/ 143 [51] Int. C1. C10G 23/04 [58] Field 01 Search 208/144, 143, 217, 111; 260/667, 683.68, 683.74; 11/57 [56] References Cited UNITED STATES PATENTS 3,197,398 7/1965 Young 208/143 3,239,449 3/1966 Grallen et a1. 208/143 3,527,695 9/1970 Lawrance et a1. 208/143 3,576,895 4/1971 Wise 260/668 A 3,647,681 3/1972 Egan 208/59 FOREIGN PATENTS OR APPLICATIONS 1,236,223 6/1971 United Kingdom 208/144 1,186,869 4/1970 United Kingdom 208/144 Primary Examiner-Delbert E. Gantz Assistant ExaminerJuanita M. Nelson Attorney, Agent, or Firm-G. 1F. Magdeburger; R. H. Davies [57] ABSTRACT A process is disclosed for reducing the amount of aromatics contaminants, and any sulfur contaminants present, in a hydrocarbon feedstock boiling in the range 500-1050F., comprised predominantly of paraffin hydrocarbons to produce a White Oil containing no more thanabout 5 ppm sulfur and 8 ppm aromatics. The feedstock, together with hydrogen, is contacted in a reaction zone with a catalyst comprising palladium and mordenite at a temperature in the range 300-700F., an LHSV from 0.1 to 20, a pressure from 100 psig to 3000 psig, and a hydrogen supply rate of 500 to 20,000 SCF/barrel of feedstock. The mordenite hasbeen exchanged to an extent of 580% of the available lion-exchange sites with a multivalent metal.

6 Claims, N0 Drawings AROMATICS HYDROGENATION IN THE PRESENCE OF SULFUR BACKGROUND OF THE INVENTION 1. Field ofthe Invention For some hydrocarbon conversion processes,.particularly for processes'forproducing White Oils, it is desirable and even necessary-tohave a hydrocarbon with as low a content of aromatics and sulfur as possible, -1 t 1 I.

Economic considerations strongly favor catalysts which (1) can remain on stream for long periods of time without regeneration, and (2) permit single-step desulfurization and hydrogenation of the feedstock with as little cracking as possible.

This invention is directed to a process combining the desirable features outlined above.

2. Description of the Prior Art Numerouspatents have issued directed to hydrogenation of aromatics. A significant number have also issued directed to hydrogenation of aromatics in the presence of 'sulfur. Exemplary of these are US. Pats. Nos. 3,239,449; 3,269,939, now Re. 26,883; 3,012,963, 3,197,398,3,527,695,and British Pat. No.

U.S. Pat. No. 3,197,398 teachesa process for the catalytic hydrogenation of hydrocarbons boiling in the range above about 300F. andcontaining up to 5% by weight of sulfur by subjecting the feedstock to the hydrogenating conditions witha catalyst comprising a zeolitic molecular sieve having a pore diameter between 6 and 14 A; and having deposited thereon a minor proportion of a Group VIII metal hydrogenating component. v 1

US. Pat; No. 3,527,695 discloses a process for the hydrogenation of aromatics in the presence of 0.1 to 1000 ppm of sulfur with a catalyst comprising palladium incorporated in a zeolite with pore openings of at least 6 A. Su'itablezeolites include Zeolite Y or faujasite, mordenite and Zeolite Z.

While the patents cited above are directed in all cases at least in a general way to the hydrogenation of aromatics in the presence of sulfur compounds, none of the references teach the low levels of aromatics and sulfur content that can be obtained using' the process and catalyst of the subject invention. Thatis, there is no teaching of'reducing both aromatics and sulfur content to less than S-ppm combined with less than 5% hydrocracking of the hydrocarbon feedstock and preferably less than 1% hydrocracking.

SUMMARY OF THE INVENTION "The subject invention is a process, which may be conducted in a single step, for reducing the amount of sulfur and aromatics contaminants in a hydrocarbon feedstockboiling in the range 500-l050F. and comprised primarily'of paraffmic hydrocarbons, by contacting the feedstock and hydrogen in a reaction zone with a catalyst comprising palladium and mordenite; The mordenite has been ion-exchanged to an extent of 580%, pref erably I0-50%, more preferably l030%, of the available ion-exchange sites with a multivalent metal, e.g.,

rare earths having an atomic weight of 57-71, calcium,

barium, strontium and magnesium. The reaction is carried out at a temperature in the range 300700F. and an LHSV from 0.1 to 20. A pressure from psig to 3000 psig is utilized. A hydrocarbon product containing nomore than about 8 ppm aromatics, preferably no more than about 5 ppm aromatics, and no more than about 5 ppm sulfur is recovered.

DETAILED DESCRIPTION OF THE INVENTIQN As described above, this invention is directed to treatment of the hydrocarbon feedstock to reduce aro- A matics contaminants to a very low level, and also to re-- (m ce to a very low level any sulfur present. For purposes of this invention, the level of hydrogenation of the aromatics must be such as to reducearomatics content in the hydrocarbon product obtained to a level of no more than about 8 ppm and preferably no more than about 1 ppm. Similarly, the level of sulfur content of the hydrocarbon product must be no more than about 5 ppm, and preferably no more than about 1 ppm, more preferably'no more than 0.1 ppm (all parts by weight).

Hydrocarbon Feedstock The hydrocarbon feedstocks utilized in the present invention boil in the range from about 500F. to 1050F. and comprise as a major portion thereof paraffinic hydrocarbons. The feedstocks previously may have been subjected to a hydrogenation treatment. The minor portion of the feedstock will include aromatics, organo-sulfur compounds, and may include unsaturated hydrocarbons such as olefins and acetylenes as well as saturated hydrocarbons, which are cyclic in nature. The aromatics content will, in general, range from 0.1 to 20 weight percent, preferably 0.1to 10 weight percentQln a particular application, the aromatics content of a feedstock containing more than 8 weight percent aromatics is reduced to less than 8 weight percent aromatics. The sulfur content will vary from 0 to 1000 ppm, preferably more than 5 ppm, for example 5-500 pp Process Conditions The conditions for carrying out the process will depend on the feedstock, the amount of sulfur present, and the extent of aromatic hydrogenation required. They fall into the following ranges:

Preferred Range Temperature, F.

300-700 400-550 Pressure, psig 100-3000 2000-3000 Space Velocity, V/V/Hr. 0.1-20 0.1-0,5 I-I, Gas Rate, SCF/bbl. SOD-20,000 5000-15,000 I temperatures are again raised to the threshold temperature. I

Catalyst Composition The catalyst of the subject invention comprises (1) I palladium and (2) mordenite, which has been ionexchanged to an'extent of from 5-80%, preferably 50%, and more preferably 10-30%, of the available exhangeable sites with'a multivalent metal. Examplary metals include the rare earths of atomic numbers 57-71, calcium, barium, strontium, and magnesium. Mordenite zeolite is described in some detail in U.S. Pats..Nos..3,647,68l and 3,576,895. No additional detailed description of the preparation is believed necessary. The hydrogen form, which is the preferred starting material for preparing the mordenite used in the subject catalyst, may be obtained by various methods, e.gl, by ion-exchanging the monovalent metal, e.g., sodium or potassium, with an ammonium salt followed by heating to decompose the zeolitic ammonium ion to form a zeolitic hydrogen ion. Alternatively, the hydrogen-form mordenite may be prepared by direct acid treatment of the alkali metal sieves. Preferably, as little monovalent metal remains in the mordenite as possible. For purposes of this invention, the mordenite may contain monovalent metals in an amount up to about 30% of the available ion-exchange sites. The hydrogen-ion form of the mordenite is ion-exhanged with a metal selected from the class consisting of rare earths of atomic numbers, 57-71, calcium, magnesium, barium and strontium, preferably calcium or mixed rare earths. The level of ion exchange for purposes of this invention must be in the range 580% of the ion-exchange sites available. If less than this number of sites are exchanged with the multivalent metal, e.g., the divalent alkaline earth rnetals or the rare earth metals, the level of hydrocracking of the resulting catalyst will be excessive at the process temperatures. lf greater than 80% of the ion-exchange sites available in the hydrogen mordenite are exchanged, the level of hydrogenation and desulfurization decreases, rendering the resulting products undesirable. It is critical for purposes of this invention that the level of ion exchange be within the range specified above.

The palladium can be combined with the mordenite either prior to or after ion-exchange treatment with the rare earths and/or alkaline earths has been completed. The palladium is preferably incorporated into the zeolite by impregnation or as a cation by ion exchange. The amount of palladium present in the mordenite will range from about 0.05 to 10 weight percent (based on the ,total catalyst), preferably 0.1 to 5 weight percent, and more preferably 0.2 to 2.5 weight percent.

Suitable compounds for combining the palladium with the mordenite include palladium chloride, palla-- dium nitrate and palladium tetraamine dinitrate.

Product Composition The hydrocarbon product recovered from the reaction zone of the subject process contains less than about 8 ppm by weight aromatics and less than about 5 ppm by weight sulfur; preferably both the aromatics and sulfur content of the hydrocarbon product will be reduced to less than 1 ppm. No more than about 5% by weight conversion to lower-boiling products by hydrocracking, preferably less than 1%, will occur. The recovered hydrocarbon product from the reaction zone EXAMPLE A catalyst of 1% palladium on a partially Caexchanged hydrogen mordenite was prepared as follows: mordenite extrudate hydrogen form) was contacted with 0.15 M calcium acetate solution at F., three times for 30 minutes each time, using fresh Ca solution for each single exchange. The calcium analyses during this procedure is given below:

0.02% weight (dry basis).

Before After one exchange 05% After two exchanges 0.8% After three exchanges 1.15

This corresponds to about 20% of the available cationic sites occupied by calcium ion.

This corresponds to about 20% of the available cationic sites occupied by calcium ion.

This extrudate was then dried in vacuo at 300F. for 24 hours and had, after drying, a pore volume of 0.32

c'c/g.

The appropriate amount of palladuim nitrate solution (10 g Pd/lOO cc) to give 1% Pd on the catalyst was contacted with the dried extrudate and shaken until all the liquid was soaked up. The material was then dried for 16 hours at 300F. in vacuo, subsequently calcined for 15 minutes at 500F., and then for 60 minutes at 900F.

This catalyst was reduced in hydrogen for two hours at 300450F. and was then used for the desulfurizationaromatics hydrogenation of a sulfurand aromatics-containing feedstock boiling in the range 500800F., to produce a White Oil.

Hydrogenation was accomplished at 2500 psig, using 10,000 SCF of hydrogen per barrel of feedon a oncethrough basis.'The hydrogenation reaction was carried out at a temperature of 400F., and a liquid hourly space velocity (LHSV) of 0.25. The resulting product was a White Oil containing less than 5 ppm aromatics and less than 0.1 ppm sulfur. The White Oil product had a UV specification of 0.13. The level of ion exchange of the catalyst is important. At lower exchange levels, the undesirable cracking activity is much higher at a given temperature than at higher exchange levels. However, more extensive exchange (50%, e.g.) reduces the desirable hydrogenation activity significantly. The optimum range is 1' O20% of the available sites exchanged. Particularly good results are obtained with catalysts containing 1% palladium on a partially calcium-exchanged hydrogen mordenite (mordenite extrudate 80% hydrogen form used).

What is claimed is? 1. A process for, without substantial hydrocracking, reducing the amount of aromatics contaminants in a hydrocarbon feedstock boiling in the range 500-1050F. and comprised predominantly of paraffins and containing from 0.1 to 20 weight percent aromatics and 0 to 1000 ppm sulfur, which comprises:

A. contacting said feedstock and hydrogen in a reaction zone with a catalyst comprising palladium and mordenite exchanged to an extent of 580% of the available ion-exchange sites with a multivalent metal at a temperature in the range 300700F., an LHSV from 0.l20, and at a pressure from to 3000 psig, and

B. recovering from said reaction zone a hydrocarbon product containing less than 8 ppm aromatics and less than ppm sulfur.

2. The process of claim 1 wherein said feedstock contains from 0.1 to 10.0 weight percent aromatics and from 5 to 500 ppm sulfur.

3. The process of claim 1 wherein said palladium is present in an amount of from 0.2 to 2.5 weight percent, based on the total catalyst, and said mordenite is exchanged to an extent of from 5% to 80% of the available ion-exchange sites with a multivalent metal selected from the class consisting of rare earths of atomic numbers 57-71, calcium, barium, strontium, and magnesium.

4. The process of claim 1 wherein said metal is a rare earth of atomic numbers 57-7l.

5. The process of claim 1 wherein mordenite is exchanged to an extent of 10 to 50% of the available ionexchange sites with a multivalent metal selected from the class of rare earths of atomic numbers 57-71, calcium, barium, strontium, and magnesium.

6. The process of claim 1 wherein mordenite is exchanged to an extent of 10 to 30% of the available ionexchange sites with a multivalent metal selected from the class of rare earths of atomic numbers 57-71, calcium, barium, strontium and magnesium. 

1. A PROCESS FOR, WITHOUT SUBSTANTIAL HYDROCRAKING, REDUCING THE AMOUNT OF AROMATICS CONTAMINANTS IN A HYDROCARBON FEEDSTOCK BOILING IN THE RANGE 500*-1050*F. AND COMPRISED PREDOMINANTLY OF PARAFFINS AND CONTAINING FROM 0.1 TO 20 WEIGHT PERCENT AROMATICS AND 0 TO 1000 PPM SULFUR, WHICH COMPRISES: A. CONTACTING SAID FEEDSTOCK AND HYDROGEN IN A REACTION ZONE WITH A ATALYST COMPRISING PALLADIUM AND MORDENITE EXCHANGED TO AN EXTENT OF 5-80% OF THE AVAILABLE ION-EXCHANGE SITES WITH A MULTIVALENT METAL AT A TEMPERATURE IN THE RANGE 300*-700*F., AN LHSV FROM 0.1-20, AND AT A PRESSURE FROM 0 TO 3000 PSIG, AND B. RECOVERING FROM SAID REACTION ZONE A HYDROCARBON PRODUCT CONTAINING LESS THAN 8 PPM AROMATICS AND LESS THAN 5 PPM SULFUR.
 2. The process of claim 1 wherein said feedstock contains from 0.1 to 10.0 weight percent aromatics and from 5 to 500 ppm sulfur.
 3. The process of claim 1 wherein said palladium is present in an amount of from 0.2 to 2.5 weight percent, based on the total catalyst, and said mordenite is exchanged to an extent of from 5% to 80% of the available ion-exchange sites with a multivalent metal selected from the class consisting of rare earths of atomic numbers 57-71, calcium, barium, strontium, and magnesium.
 4. The process of claim 1 wherein said metal is a rare earth of atomic numbers 57-71.
 5. THe process of claim 1 wherein mordenite is exchanged to an extent of 10 to 50% of the available ion-exchange sites with a multivalent metal selected from the class of rare earths of atomic numbers 57-71, calcium, barium, strontium, and magnesium.
 6. The process of claim 1 wherein mordenite is exchanged to an extent of 10 to 30% of the available ion-exchange sites with a multivalent metal selected from the class of rare earths of atomic numbers 57-71, calcium, barium, strontium and magnesium. 